Because schools are generally funded by the government, they are generally purchased by the government. As you said, lamps and lanterns are generally not invited to bid, and those with stable market prices and low costs are directly taken, that is, at most, no competition and no inquiry. However, if it is newly built or renovated, if it is linked to the project, it is necessary to invite tenders. There are also some schools that are afraid of trouble when auditing, and invite tenders for projects no matter how small, but this situation is rare.